Now, this is just one poll. We don’t know whether those who have shifted to the Lib Dems will shift back as the memory of yesterday’s debate fades or if Clegg is less impressive in the next two debates. Looking at yesterday’s numbers—when the Tories were on 37, Labour 31 and the Lib Dems 22—it seems that Lib Dems have taken votes from both the main parties.
Tonight’s results are spectacular for the Lib Dems. The Lib Dems have always claimed that more people would support them if people thought they could win. In the next few days, we are going to find out how true that is. The Lib Dems are also going to come under a whole new level of scrutiny. But the leaders' debate have given Nick Clegg the opportunity of a real electoral breakthrough.